Assessment of interactive effects of temperature and air pollution on mortality in Mexico City

Abstract

Environmental conditions such as air pollution and ambient temperature, can pose increased risk of premature mortality. In Mexico City, despite recent improvements in reducing air pollution, ozone and particulate matter continue to contribute to thousands of deaths each year, with mounting evidence of interactive effects (synergy) between temperature and air pollution on mortality. As global temperatures rise and become more volatile, there is a growing need to untangle these relationships in order to mitigate future pollution-related mortality. This study investigated potential interactions between temperature and air pollution, specifically ozone and PM2.5, on all-cause, cardiovascular disease, and respiratory disease mortality. Daily mortality counts were modelled using generalized additive models (GAMs), adjusting for long term and seasonal trends in mortality. Bivariate response surface models and parametric models indicate interaction between air pollution and temperature. In particular, risk of mortality due to PM2.5 was significantly heightened at colder temperatures. This study highlights the importance of reducing air pollution exposure, particularly during periods of anomalously cold temperature.